I want to know if you looked inside the cylinder and could see the piston when it was at TDC when you set your valves. I always take a rubber hose and make sure I'm not at BDC. The valves are closed at both and it would be easy to make a mistake.
The exhaust valve opens at around 60-70 degrees BEFORE BDC as the piston travels down on the power stroke, and remains open until around 30-40 degrees ATDC as the intake stroke is beginning. The intake valve opens at around 30-40 degrees BTDC as the exhaust stroke is ending, and stays open until about 60-70 degrees AFTER BDC as the compression stroke begins. Thus, there is no BDC in the 4 stroke cycle at which one valve is not open.